The present invention relates to a snapshot management device and snapshot management method suitable for use in a storage system.
Snapshot is one of the conventional techniques used in network storage such as a Network Attached Storage (NAS). It is a technique to maintain a static image of a file system at a certain point in time while maintaining the latest status of the file system by updating the file therein.
Snapshots are used for online backup which enables backup using snapshots even when updating file systems, and for file recovery when a file is mistakenly updated or deleted by a user.
In recent years, a proposal has been made to obtain a plurality of generations of snapshots, for example, in Japanese Patent Laid-Open Publication No. 2004-342050. Using the technique disclosed in this document, it is possible to sequentially mount a plurality of snapshots obtained on a regular basis and to set up a file-sharing configuration for the snapshots in the NAS so as to make them public to multiple users.